Analysis of Heavy Oil Production by Radio-Frequency Heating

Abstract

During last decades the major companies increasingly exploit such hydrocarbon resources as heavy oil, bitumen or oil shale. The production of oil from such reservoirs is frequently done through reservoir heating, most often via steam injection. However it becomes more and more evident that for some cases there exist better suited technologies and one of them is the electromagnetic (EM) heating assisted oil recovery. According to the EM field frequency different physical mechanisms may underlie the heat release. The radio-frequency (RFH) or dielectric heat generation results from rotation with friction of polar molecules in the EM field. The advantages of the RFH-based technology are related to the in-situ heating and steam generation from the connate water which eliminates the problems associated with low well injectivity, well injection pressure, the water supply and hence, the water treatment etc. They include also the possibility to apply the heating in shallow or thin reservoirs and also in case of initially mobile heavy oil to optimize the production efficiency using both principal production mechanisms: the gravity drainage and the steam drive. The large-scale RFH models have been recently developed for numerical simulation of realistic EM power distributions. These models provide a means to critically analyze the processes of oil recovery. In the current study we take advantage of two dedicated simulators and the methodology of loose coupling between them to deliver the calculated EM heating power field to dedicated reservoir simulator. The combination and competition between two principal production mechanisms for different well patterns, spacing and orientation are considered; their influence together with other operational conditions impact on the efficiency and application limits of the oil recovery method are analyzed. The analysis of different mechanisms of RFH assisted heavy oil production is an important feature in process design considerations.

Electrical Heating for Heavy Oil: Past, Current, and Future Prospect

“…Radio-frequency (RF) technology which is often applied for the cumulative acquisition of heavy oil around the borehole [67], [68]. Literature shows Radio Frequency Heating is more practical than electrical resistive for surface oil sand which RFH is cheaper, quicker and heating is uniform and deeper than ERH, with oil recoveries ranging from 50 to 80% [58], when the RF process occurs continuously and provides excessive heat around the borehole, and it can damage the integration around the borehole and equipment from the radio frequency [69].…”

Heavy Oil Recovery via Combination of Radio-Frequency Heating With Solvent Injection

“…Non-condensable gas injection in the RFH framework has been studied numerically in Bogdanov et al (2014). The main objective was to define the potential of the vertical gravity-stabilized displacement of HO via injection of non-condensable gas from the top of reservoir at low power RFH.…”

“…Note that significantly higher heating power is required to provide the necessary drive at pure RFH without supplementary gas injection (eg. Bogdanov et al 2014).…”

“…the total additional drive induced by the RFH which in fact is as a special case of steam drive occurring at variable shape of in-situ steam generation surface. In Bogdanov et al (2014) it was shown that within the chosen range of power for initially mobile HO the RFH drive influence region is limited by the gas chamber (GC) volume. Increased power resulted in faster expansion of the GC, stimulates the RFH drive and contributes to higher oil production rate which leads also to improved energy efficiency.…”

“…Although limited in computational performance this approach can be successfully used for field-scale simulations (cf. Bogdanov et al 2014).…”